In general, detergent compositions contain various surfactants in order to improve the washing effects and to give a refreshing feel after washing. For example, alkyl sulfates, polyoxyethylene alkyl sulfates and alkyl benzenesulfonates have been used as a surfactant. However, these surfactants are relatively highly irritative to the skin or hair and the use of them tends to cause excessive removal of the sebum due to the high washing effects thereof, accompanied by dry-up, stretched feel and decrease in the moistness. Because of this, less irritative surfactants such as alkyl phosphates and acylated amino acid salts have been used as a surfactant or an emulsifier in skin or hair detergents or cosmetics.
However, the recent consumers' fondness for high-grade and diversified products has made it necessary to develop a compound which is not only less irritative to the skin, but also exerts a conditioning effect of imparting a preferable feel to the skin or hair and can be blended in skin or hair detergents.
To improve a moist feel of the skin or hair after washing, it has been attempted to use cosmetic lotions or milky lotions containing humectants. It has also been attempted to add humectants to hair or skin detergents such as shampoos in order to impart a moist feel to the hair or skin.
However, since conventional humectants are soluble in water, while the detergents have to be washed away with water after the use, humectants contained in the detergents are also washed away with water. When these humectants are used in such a large amount that sufficient humidifying effects remain after washing away with water, there arises another problem that the feel at the use (for example, stickiness) is worsened.
Therefore, it has been required to develop a detergent composition which exerts sufficient humidifying effects without causing any unpleasant feel such as stickiness.
On the other hand, various humectants exerting protecting effects on the skin or hair have been employed in cosmetics. Examples of humectants which have been employed in practice include propylene glycol, glycerol, urea, sorbitol and alkylene oxide adducts of alcohols.
However, none of these humectants is satisfactory in humidifying properties, hygroscopicity, hygroscopic rate or feel at the use. Although natural polysaccharides such as hyaluronic acid are relatively excellent in humidifying properties and the feel at the use, they are expensive and thus application thereof is exclusively restricted to, for example, relatively high-grade cosmetics.
Accordingly, it has been required to develop a compound which is excellent in humidifying properties, inexpensive and applicable to detergents such as a shampoo or cosmetics such as a hair conditioner and the like.
Furthermore, since conventional humectants are soluble in water, they are prone to be removed from the skin or hair by water or perspiration and thus frequently fail to fully exert the inherent effects when they are used at, for example, swimming pool or when they are contained in cosmetics to washed away with water (for example, hair conditioners and body conditioners). When these humectants are used in such a large amount that sufficient humidifying effects remain after washing away with water, there arises another problem that the feel at the use (for example, stickiness) is worsened.
Therefore, it has also been required to develop a cosmetic which is highly resistant to sweat, can sustain a sufficient humidifying effects after washing with water and impart a less sticky but moist feel.